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Photo Gallery

At a distance of 6,000 light years from Earth, the star cluster RCW 38 is a relatively close star-forming region. This image covers an area about five light years across, and contains thousands of hot, very young stars formed less than a million years ago. X-rays from the hot upper atmospheres of 190 of these stars were detected by NASA's Chandra X-ray Observatory. In addition to the point-like emission from stars, the Chandra image revealed a diffuse cloud of X-rays enveloping the star cluster. The X-ray spectrum of the cloud shows an excess of high-energy X-rays, which indicates that the X-rays come from trillion-volt electrons moving in a magnetic field. Such particles are typically produced by exploding stars, or in the strong magnetic fields around neutron stars or black holes, none of which is evident in RCW 38. +
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The Chandra image of a binary star system known as SS 433 shows two high-speed lobes of 50-million-degree gas that are 3 trillion
miles apart on opposite sides of a binary black hole system. As shown in the illustration (lower right), the binary system, which has a
diameter several million times smaller than the distance between the lobes, consists of a massive star and a black hole with a disk of hot matter. + Read More

The Chandra X-ray Observatory image of NGC 6240 -- a butterfly-shaped galaxy that is the product of the collision of two smaller
galaxies -- revealed that the central region of the galaxy (inset) contains not one, but two active giant black holes. Previous X-ray
observatories had shown that the central region was an X-ray source, but astronomers did not know what was producing the X-rays. Radio, infrared, and optical observations had detected two bright nuclei, but their exact nature also remained a mystery. + Read More

This remarkable image from the Chandra X-ray Observatory image gave scientists their first look at X-rays from Mars. In the
sparse upper atmosphere of Mars, about 75 miles above its surface, the observed X-rays are produced by fluorescent radiation from oxygen atoms. X-rays from the Sun impact oxygen atoms, knock electrons out of the inner parts of their electron clouds, and excite the atoms to a higher energy level in the process. The atoms almost immediately return to their lower energy state and may emit a fluorescent X-ray in this process with an energy characteristic of the atom involved -- oxygen in this case. A similar process involving ultraviolet light produces the visible light from fluorescent lamps. + Read More

Keith Hefner has been named program manager for NASA's Chandra X-ray Observatory at NASA's Marshall Space Flight Center in
Huntsville, Ala. A native of Boaz, Ala., he will be responsible for planning, budgeting and operations for the world's most powerful X-ray telescope. Hefner joined Marshall in 1985.

An image from NASA's Chandra X-ray Observatory of galaxy NGC 720 shows the galaxy enveloped in a slightly flattened, or
ellipsoidal cloud of hot gas that has an orientation different from that of the optical image of the galaxy. The flattening is too large to be
explained by theories in which stars and gas are assumed to contain most of the mass in the galaxy. According to the standard theory of gravity, the X-ray producing cloud would need an additional source of gravity -- a halo of dark matter - to keep the hot gas from expanding away. The mass of dark matter required would be about five to 10 times the mass of the stars in the galaxy. + Read More

A series of Chandra images has allowed scientists to trace the evolution of large-scale X-ray jets produced by a black hole in a
binary star system. As the schematic shows, gaseous matter pulled from a normal star forms a disk around the black hole. The gas is heated to temperatures of millions of degrees, and intense electromagnetic forces in the disk can expel jets of high-energy particles. An outburst of X-rays from the source, XTE J1550-564, was detected by NASA's Rossi X-ray Timing Explorer (RXTE) in 1998. + Read More

The Chandra images in this collage were made over a span of several months (ordered left to right, except for the close-up). They
provide a stunning view of the activity in the inner region around the Crab Nebula pulsar, a rapidly rotating neutron star seen as a bright white dot near the center of the images. A wisp can be seen moving outward at half the speed of light from the upper right of the inner ring around the pulsar. The wisp appears to merge with a larger outer ring that is visible in both X-ray and optical images. + Read More

A Chandra observation of the galaxy cluster A2104 revealed six bright X-ray sources that are associated with supermassive black
holes in red galaxies in the cluster. Since red galaxies are thought to be composed primarily older stars, and to contain little gas, the
observation came as a surprise to astronomers. Powerful X-ray emission from a supermassive black hole comes from gas heated as it falls toward the black hole, so an abundant supply of gas is needed to produce the bright X-ray sources detected by Chandra. + Read More

This Chandra image reveals fascinating details of the turbulent debris created by a supernova explosion observed by the Danish
astronomer Tycho Brahe in 1572. The colors show different X-ray energies, with red, green, and blue representing low, medium and high energies, respectively. The image is cut off at the bottom because the southernmost region of the remnant fell outside the field of view of the detector. A shock wave produced by the expanding debris is outlined by the strikingly sharp blue circular arcs of twenty million degree Celsius gas seen on the outer rim. The stellar debris, which has a temperature of about ten million degrees and is visible only in X-rays, shows up as mottled yellow, green and red fingers of gas. + Read More

A composite X-ray (blue), radio (pink and green), and optical (orange and yellow) image of the galaxy Centaurus A presents a stunning tableau of a galaxy in turmoil. A broad band of dust and cold gas is bisected at an angle by opposing jets of high-energy particles blasting away from the supermassive black hole in the nucleus. Two large arcs of X-ray emitting hot gas were discovered in the outskirts of the galaxy on a plane perpendicular to the jets. The arcs of multimillion-degree gas appear to be part of a projected ring 25,000 light years in diameter. + Read More

The Chandra image of NGC 1569, a dwarf galaxy 7 million light years from Earth, shows large hot bubbles, or lobes extending above and below a disk of gas along the equator of the galaxy. The 27-hour observation allowed scientists to measure for the first time the concentration of oxygen, neon, magnesium, and silicon in the bubbles and the disk. They found that bubbles contain oxygen equal to the oxygen contained in 3 million suns. For the last 10 million to 20 million years NGC 1569 has been undergoing a burst of star formation and supernova explosions, perhaps triggered by a collision with a massive gas cloud. + Read More

X-rays from a rare type of supernova in the Whirlpool Galaxy were recently observed, thanks to the fine resolution of NASA's Chandra X-ray Observatory. The team of researchers also detected a large number of point-like X-ray sources due to black holes and neutron stars in binary star systems. Chandra's image highlights the energetic central regions of the two interacting galaxies, NGC 5194 (center) and its smaller companion (upper left) NGC 5195, that are collectively called the Whirlpool Galaxy. + Read More

The Chandra image of the distant supernova Remnant SNR G54.1+0.3 reveals a bright ring of high-energy particles with a central point-like source. This observation enabled scientists to use the giant Arecibo Radio Telescope to search for and locate the pulsar, or neutron star that powers the ring. The ring of particles and two jet-like structures appear to be due to the energetic flow of radiation and particles from the rapidly spinning neutron star. + Read More

This artist's conception illustrates 1E 1207.4-5209, a neutron star with a polar hot spot and a strong magnetic field (purple lines). The
neutron star is about 7,000 light years from Earth. The graph in the box to the right of the star shows the expected (dashed blue line) and the observed (solid green line) spectra of the X-radiation from the hot spot. The dips in the observed spectrum are absorption features due to gas in the atmosphere of the neutron star. + Read More

Chandra's image of the elliptical galaxy NGC 4697 reveals diffuse hot gas dotted with many point-like sources. As in the elliptical galaxies, NGC 4649 and NGC 1553, the point-like sources are due to black holes and neutron stars in binary star systems. Material pulled off a normal star is heated and emits X-radiation as it falls toward its black hole or neutron star companion. Black holes and neutron stars are the end state of the brightest and most massive stars. + Read More

Chandra's image of the lenticular -- an elliptical-type galaxy with a disk of old stars -- galaxy NGC 1553 reveals diffuse hot gas dotted with many point-like sources. As in the elliptical galaxies, NGC 4649 and NGC 4697, the point-like sources are due to black holes and neutron stars in binary star systems where material pulled off a normal star is heated and emits X-radiation as it falls toward its black hole or neutron star companion. + Read More

Chandra's image of the elliptical galaxy NGC 4649 reveals a large, bright cloud of hot gas and 165 point-like sources. As in the elliptical galaxies, NGC 4697 and NGC 1553, most of the point-like sources are due to black holes and neutron stars in binary star systems. Black holes and neutron stars are the end state of the brightest and most massive stars. Chandra's detection of numerous neutron stars and black holes in this and other elliptical galaxies shows that these galaxies once contained many very bright, massive stars, in marked contrast to the present population of low-mass faint stars that now dominate elliptical galaxies. + Read More

Every 64 hours, NASA's Chandra X-ray Observatory follows a path that dodges darkness, stretches one-third of the way to the Moon, and has a more elliptical shape than most orbiting satellites. Chandra's unique orbit was selected by, from left, Russell Stone, Steve Evans and Larry Mullins, all of NASA's Marshall Space Flight Center in Huntsville, Ala.

This "true color" Chandra image of N132D shows the beautiful, complex remnant of an explosion of a massive star in the Large Magellanic Cloud, a nearby galaxy about 180,000 light years from Earth. The colors represent different ranges of X-rays, with red, green, and blue representing, low, medium, and higher X-ray energies respectively. Supernova remnants comprise debris of a stellar explosion and any matter in the vicinity that is affected by the expanding debris. In the case of N132D, the horseshoe shape of the remnant is thought to be due to shock waves from the collision of the supernova ejecta with cool giant gas clouds. As the shock waves move through the gas they heat it to millions of degrees, producing the glowing X-ray shell. + Read More

The Chandra image of Arp 270 shows two galaxies about 90 million light years from Earth in the early stage of a merger. The future evolution of these galaxies will be radically changed by the merger as their mutual gravity distorts their shape, and the collision of gas clouds in the galaxies stimulates the formation of new stars. The hot spots (blue) located where the disks of the galaxies are colliding are thought to be due to the formation of hundreds of thousands of new stars as the two gaseous disks rotate through each other. + Read More

The Chandra image of the Tarantula Nebula gives scientists a close-up view of the drama of star formation and evolution. The Tarantula, also known as 30 Doradus, is in one of the most active star-forming regions in our local group of galaxies. Massive stars are producing intense radiation and searing winds of multimillion-degree gas that carve out gigantic super-bubbles in the surrounding gas. + Read More

The Chandra observations of the peculiar galaxy Arp 220 gives new insight into what happens when two galaxies the size of the Milky Way collide. The image shows a bright central region at the waist of a glowing hour-glass-shaped cloud of multimillion degree gas that is rushing out of the galaxy at hundreds of thousands of miles per hour. This "superwind" is thought to be due to explosive activity generated by the formation of hundreds of millions of new stars. + Read More

Chandra observations of RXJ1856.5-3754 and the pulsar in 3C58 suggest that the matter in these collapsed stars is even denser than nuclear matter, the most dense matter found on Earth. This raises the possibility that these stars are composed of free quarks or crystals of sub-nuclear particles, rather than neutrons. By combining Chandra and Hubble Space Telescope data, astronomers found that RXJ1856 radiates like a solid body with a temperature of 700,000 degrees Celsius and has a diameter of about 7 miles. + Read More

Chandra observations of RXJ1856.5-3754 and the pulsar in 3C58 suggest that the matter in these collapsed stars is even denser than nuclear matter, the most dense matter found on Earth. This raises the possibility that these stars are composed of free quarks or crystals of sub-nuclear particles, rather than neutrons. By combining Chandra and Hubble Space Telescope data, astronomers found that RXJ1856 radiates like a solid body with a temperature of 700,000 degrees Celsius and has a diameter of about 7 miles. + Read More

This Chandra image shows the central region -- about 1.5 million light years across -- of the Coma Cluster. The cluster contains thousands of galaxies enveloped by a vast 100 million-degree Celsius gas cloud. Of particular interest are the concentrations of cooler (10 to 20 million-degrees) gas around the large galaxies NGC 4874 (left), and NGC 4889 (right). These clumps of gas, which are 10,000 light years in diameter, are thought to be produced by matter ejected from stars in the galaxies over a period of about a billion years. + Read More

These three quasars, recently discovered at optical wavelengths by the Sloan Digital Sky Survey, are 13 billion light years from Earth, making them the most distant known quasars. The X-rays Chandra detected were emitted when the universe was only a billion years old, about 7 percent of the present age of the universe. A surprising result was that the power output and other properties of these quasars are similar to less distant quasars. This indicates that the conditions around these quasars' central supermassive black holes must also be similar, contrary to some theoretical expectations. + Read More

The Chandra image of the twin quasar Q2345+007 A, B shows that they are not identical twins. This means that it is unlikely that they are an optical illusion, rather, they were probably created by merging galaxies. When galaxies collide, the flow of gas onto the central supermassive black holes of each of the galaxies can be enhanced, resulting in two quasars. The light from the quasar pair started its journey toward Earth 11 billion years ago. Galaxies were about three times closer together then than they are now, so collisions were much more likely. + Read More

This image of Jupiter shows concentrations of auroral X-rays near the north and south magnetic poles. While Chandra observed Jupiter for its entire 10-hour rotation, the northern auroral X-rays were discovered to be due to a single `hot spot' that pulsates with a period of 45 minutes, similar to high-latitude radio pulsations previously detected by NASA's Galileo and Cassini spacecraft. + Read More

Chandra's image of the extremely hot galaxy cluster 1E0657-56 reveals a bow-shaped shock wave toward the right side of the cluster. This feature, thought to be the result of the merger of a smaller group or sub-cluster of galaxies with 1E0657-56, gives astronomers a rare opportunity to study how clusters grow. The shock wave appears to have been formed as 70 million degree Celsius gas in the sub-cluster plowed through 100 million degree gas in the main cluster at a speed of about 6 million miles per hour. This motion created a wind that stripped the cooler gas from the sub-cluster, similar to leaves from a tree being blown off in a storm. + Read More

The X-ray image of the quasar PKS 1127-145, a highly luminous source of X-rays and visible light about 10 billion light years from Earth, shows an enormous X-ray jet that extends at least a million light years from the quasar. The jet is likely due to the collision of a beam of high-energy electrons with microwave photons. The high-energy beam is thought to have been produced by explosive activity related to gas swirling around a supermassive black hole. The length of the jet and the observed bright knots of X-ray emission suggest that the explosive activity is long-lived but intermittent. +
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The Chandra image of the Centaurus galaxy cluster shows a long plume-like feature resembling a twisted sheet. The plume is some 70,000 light years in length and has a temperature of about 10 million degrees Celsius. It is several million degrees cooler than the hot gas around it, as seen in this temperature-coded image in which the sequence red, yellow, green, blue indicates increasing gas temperatures. + Read More

This 400 by 900 light-year mosaic of several Chandra images of the central region of our Milky Way galaxy reveals hundreds of white dwarf stars, neutron stars, and black holes bathed in an incandescent fog of multimillion-degree gas. The supermassive black hole at the center of the galaxy is located inside the bright white patch in the center of the image. The colors indicate X-ray energy bands - red (low), green (medium), and blue (high). + Read More

This X-ray image of the galaxy cluster Abell 2597, taken by NASA's Chandra X-ray Observatory, shows a vast bright cloud of hot gas with two cavities on the upper left and lower right, about 100,000 light years from the center of the cluster. These so-called ghost cavities are thought to be 100-million-year old relics of an ancient eruption that originated around a supermassive black hole in the core of a centrally located galaxy. + Read More